Vehicle seat

ABSTRACT

Provided is to stabilize a fixed state of each bag body provided at a vehicle seat and configured to expand to push a corresponding one of the shoulders of a seated passenger. Of a seat back provided at the vehicle seat, each shoulder support configured to support a corresponding one of the shoulders of the seated passenger includes an air cell configured to expand by injection of air. The air cell includes protrusions extending in a predetermined direction and provided at respective end portions of the air bag in the extending direction thereof. The air cell is attached to the inside of the seat back in such a manner that each of the protrusions provided at respective end portions in the extending direction is fixed to a corresponding one of fixing positions separated from each other in the width direction of the vehicle seat.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a National Stage Entry application of PCTApplication No. PCT/JP2015/064259, filed May 19, 2015, which claims thepriority benefit of Japanese Patent Application No. JP2014-103593, filedMay 19, 2014, the contents being incorporated herein by reference.

BACKGROUND

The present disclosure relates to a vehicle seat, and particularlyrelates to a vehicle seat including an expandable bag body at shouldersupport portions configured to support a corresponding one of theshoulders of a seated passenger, each shoulder support portion beingprovided at a seat back configured to support the seated passenger froma back side.

Among vehicle seats, there is a vehicle seat including, in a seat back,an expandable/contractible bag body such as an air cell for the purposeof, e.g., adjustment of a seating posture of a seated passenger.According to the seat with such a configuration, a seating surface shapeis changed by expansion/contraction of the bag body so that the seatingposture can be adjusted. Examples of the seat including theexpandable/contractible bag body include a seat described in JapanesePatent No. 2664599.

In the seat described in Japanese Patent No. 2664599, each of an upperbag portion and a lower bag portion in a seat back includes an air matas a bag body, and a support panel at a front position of the air mat.By expansion of the air mat, the support panel tilts forward to push theback of a seated passenger forward, and in this manner, a seatingposture of the seated passenger is adjusted. Particularly in the upperbag portion, when the support panel tilts forward by expansion of theair mat, the shoulders of the back of the seated passenger are pushedforward.

Note that the examples of the seat including the expandable/contractiblebag body include seats other than the vehicle seat, and as an example,there is a relaxing chair described in Japanese Patent Publication JP2001-112565. In a bag body provided in this relaxing chair, any ofliquid, fluid, a mixture of liquid and grains, and solid containingflexibility is housed as a medium. When a user is seated on the relaxingseat and leans on a back portion of the relaxing seat, theabove-described bag body comes into close contact with the back of theseated user. As a result, a favorable feeling of fitting can be providedto the seated user of the relaxing chair.

In order to properly adjust the seating posture of the seated passengerand properly provide the favorable feeling of fitting, the bag bodyprovided in the seat needs to properly expand/contract at an arrangementposition of the bag body. For proper expansion/contraction, a directionin expansion of the bag body needs to be stabilized. In order tostabilize such a direction, a fixed state of the bag body needs to bestabilized. Particularly in proper adjustment of the degree of pushing(pressing force) of the bag body pushing the vicinity of a correspondingone of the shoulders of the passenger seated on the seat, the fixedstate of the bag body needs to be further stabilized. On the other hand,Japanese Patent No. 2664599 and Japanese Patent Publication JP2001-112565 describe the arrangement position of the bag body, but donot mention the way to fix the bag body. That is, a specificconfiguration for stabilizing the fixed state of the bag body is notclearly described in Japanese Patent No. 2664599 and Japanese PatentPublication JP 2001-112565.

In addition to the above-described demand for stabilizing the fixedstate of the bag body pushing the vicinity of a corresponding one of theshoulders of the seated passenger, it has been demanded that such a bagbody is fixed at a proper position to properly push a corresponding oneof the shoulders of the seated passenger. Further, in the configurationin which the shoulders of the seated passenger are pushed through theplate-shaped member disposed at the front position of the bag body asdescribed in Japanese Patent No. 2664599, the plate-shaped member needsto be supported so that the plate-shaped member can fulfill functionsthereof.

SUMMARY

The present disclosure has been made in view of the above-describedproblems, and an embodiment of the present disclosure provides a vehicleseat that stabilizes a fixed state of each bag body configured to expandto push a corresponding one of the shoulders of a seated passenger. Anembodiment of the present disclosure also fixes each bag body at such aposition that a corresponding one of the shoulders of the seatedpassenger can be properly pressed. An embodiment of the presentdisclosure properly supports a plate-shaped member disposed at a frontposition of each bag body in the configuration in which the shoulders ofthe seated passenger are pushed through the plate-shaped member.

The above-described problems are solved by an embodiment of a vehicleseat of the present disclosure. An embodiment of the vehicle seat of thepresent disclosure is a vehicle seat including a seat back configured tosupport a seated passenger from a back side of the seated passenger. Ashoulder support portion provided at the seat back and configured tosupport each shoulder of the seated passenger includes a bag bodyconfigured to expand by injection of fluid. The bag body includes fixingtarget portions at respective end portions of the bag body in theextending direction thereof, and is attached to the inside of the seatback in such a manner that each of the fixing target portions is fixedto a corresponding one of fixing positions separated from each other inthe width direction of the vehicle seat.

According to the above-described vehicle seat, the bag body is fixed atboth end portions of the bag body in the extending direction thereof,and therefore, a fixed state of the bag body is stabilized. Moreover,the positions (e.g., the fixing positions) at which the bag body isfixed are positions different from each other in the width direction ofthe vehicle seat, i.e., the direction along a shoulder width of theseated passenger. With this configuration, when the bag body is fixedalong the shoulder width of the seated passenger, the fixed state of thebag body is further stabilized.

In an embodiment of the above-described vehicle seat, the fixing targetportions are preferably provided in a lower region at the end portionsof the bag body in the extending direction thereof. According to theabove-described configuration, an upper region of the bag body is notfixed, and therefore, the upper region easily moves forward in expansionof the bag body. With this configuration, the bag body configured toexpand to push a corresponding one of the shoulders of the seatedpassenger expands in such a direction that the shoulders of the seatedpassenger are properly pressed.

In an embodiment of the above-described vehicle seat, the fixingposition for the fixing target portion of the fixing target portionsprovided at respective end portions of the bag body in the extendingdirection thereof located in the inner side in the width direction ismore preferably a position deviating, in both of a height direction anda width direction of the vehicle seat, from a region corresponding tothe shoulder blades of the seated passenger on the vehicle seat. In theabove-described configuration, when the passenger is seated on thevehicle seat, the fixing position which is included in the fixingpositions for the fixing target portions provided at respective endportions of the bag body in the extending direction thereof and which isfor the fixing target portion on the inner side in the width directionis the position apart from the shoulder blades of the seated passenger.With this configuration, a feeling of discomfort of the seated passengerwhen the above-described fixing positions are at positions (simply, backpositions of the shoulder blades) overlapping with the shoulder bladesin a front-to-back direction can be reduced.

In an embodiment of the above-described vehicle seat, an arrangementposition of the bag body is much more preferably a position deviating,in the width direction, from a region corresponding to the backbone ofthe seated passenger on the vehicle seat. In the above-describedconfiguration, the arrangement position of the bag body is the positionapart from the backbone of the passenger seated on the vehicle seat.With this configuration, the horizontal width (the length in the widthdirection of the vehicle seat) of the bag body is more shortened ascompared to the configuration in which the arrangement position of thebag body reaches the region corresponding to the backbone in the widthdirection of the vehicle seat, and the size of the bag body can bereduced.

In an embodiment of the above-described vehicle seat, the fixingposition for the fixing target portion of the fixing target portionsprovided at respective end portions of the bag body in the extendingdirection thereof located in the outer side in the width direction ismore preferably a position deviating, in both of the height directionand the width direction of the vehicle seat, from a region correspondingto the trapezius of the seated passenger on the vehicle seat. In theabove-described configuration, when the passenger is seated on thevehicle seat, the fixing position which is included in the fixingpositions for the fixing target portions provided in the respective endportions of the bag body in the extending direction thereof and which isfor the fixing target portion on the outer side in the width directionis the position apart from the trapezius of the seated passenger. Withthis configuration, a feeling of discomfort of the seated passenger whenthe above-described fixing positions are at positions (simply, backpositions of the trapezius) overlapping with the trapezius in thefront-to-back direction can be reduced.

In an embodiment of the above-described vehicle seat, the seat back muchmore preferably includes a seat back frame forming a framework of theseat back, and a plate-shaped fixing member disposed between one endportion and the other end portion of the seat back frame in the widthdirection, and the fixing positions are much more preferably on a frontsurface of the fixing member. According to the above-describedconfiguration, the bag body is attached to the front surface of thefixing member, and therefore, can be favorably supported. Moreover, thebag body is, in expansion, controlled by the fixing member to expandforward, and therefore, can expand to properly push a corresponding oneof the shoulders of the seated passenger.

In an embodiment of the above-described vehicle seat, the fixingposition for the fixing target portion of the fixing target portionsprovided at respective end portions of the bag body in the extendingdirection thereof located in a lower side is much more preferably in alower region of the front surface. In the above-described configuration,the fixing position which is included in the fixing positions for thefixing target portions provided in the respective end portions of thebag body in the extending direction thereof and which is for the fixingtarget portion on the lower side is in the lower region of the frontsurface of the fixing member. With this configuration, the height (thelength in an upper-to-lower direction) of the fixing member is moreshortened as compared to the case where the above-described fixingpositions are in a center region of the front surface of the fixingmember, and an increase in the size of the fixing member can besuppressed.

In an embodiment of the above-described vehicle seat, the seat back morepreferably includes a plate-shaped member disposed at a front positionof the bag body. The plate-shaped member more preferably includes adeformable portion having a back surface contacting the bag body andconfigured to deform by expansion of the bag body contacting the backsurface, and an extension positioned lower than the deformable portionand extending downward. The plate-shaped member is more preferablysupported by a support body provided in the seat back. A portion of theplate-shaped member supported by the support body is more preferablyprovided between the deformable portion and the extension. In theabove-described configuration, the plate-shaped member disposed at thefront position of the bag body includes the deformable portionconfigured to change in association with expansion of the bag body, andthe extension extending downward. The plate-shaped member is supportedby the support body at the point positioned between the deformableportion and the extension. With this configuration, the plate-shapedmember can be supported without difficulty in deformation of thedeformable portion. That is, in the above-described configuration, theplate-shaped member can be properly supported while the deformableportion can favorably deform.

In an embodiment of the above-described vehicle seat, the position ofthe portion of the plate-shaped member supported by the support body ispreferably a position reaching, in both of the height direction and thewidth direction of the vehicle seat, a region corresponding to the ninthcervical spine of the seated passenger on the vehicle seat. In theabove-described configuration, the position of the portion of theplate-shaped member supported by the support body is the positionreaching the region corresponding to the ninth cervical spine of theseated passenger. At the position of the ninth cervical spine, adisplacement when a seating posture of the seated passenger changes isrelatively small. Thus, as long as a support position of theplate-shaped member reaches the region corresponding to the ninthcervical spine, a support state of the plate-shaped member can bestabilized.

In an embodiment of the above-described vehicle seat, the seat back morepreferably includes the seat back frame forming the framework of theseat back, and the plate-shaped fixing member disposed between one endportion and the other end portion of the seat back frame in the widthdirection. The fixing positions are more preferably on the front surfaceof the fixing member. The position of the portion of the plate-shapedmember supported by the support body and the fixing positions on thefront surface are more preferably positions different from each other inthe width direction. In the above-described configuration, the positionof the portion of the plate-shaped member supported by the support bodyand the fixing positions of the bag body provided on the front surfaceof the fixing member are the positions different from each other in thewidth direction of the vehicle seat. With such a position relationship,contact between the portion of the plate-shaped member supported by thesupport body and the bag body can be reduced.

According to an embodiment of the present disclosure, the bag body isfixed at such a position that a corresponding one of the shoulders ofthe seated passenger can be properly pushed, and the fixed state of thebag body is further stabilized. Moreover, according to an embodiment ofthe present disclosure, the bag body configured to expand to push acorresponding one of the shoulders of the seated passenger expands insuch a direction that such a shoulder of the seated passenger isproperly pressed. Further, according to an embodiment of the presentdisclosure, the feeling of discomfort of the seated passenger when thefixing position which is included in the fixing positions for the fixingtarget portions provided at the bag body and which is for the fixingtarget portion on the inner side in the width direction overlaps withthe shoulder blades in the front-to-back direction can be reduced. Inaddition, according to an embodiment of the present disclosure, the sizeof the bag body can be more reduced as compared to the configuration inwhich the arrangement position of the bag body reaches the regioncorresponding to the backbone in the width direction of the vehicleseat. Moreover, according to an embodiment of the present disclosure,the feeling of discomfort of the seated passenger when the fixingposition which is included in the fixing positions for the fixing targetportions provided at the bag body and which is for the fixing targetportion on the outer side in the width direction overlaps with thetrapezius in the front-to-back direction can be reduced. Further,according to an embodiment of the present disclosure, the bag body isfavorably supported on the front surface of the fixing member. Inexpansion, the bag body is controlled by the fixing member to expandforward, thereby properly pushing a corresponding one of the shouldersof the seated passenger. In addition, according to an embodiment of thepresent disclosure, an increase in the size of the fixing member can besuppressed. Moreover, according to an embodiment of the presentdisclosure, the plate-shaped member can be properly supported while thedeformable portion of the plate-shaped member can favorably deform.Further, according to an embodiment of the present disclosure, thesupport state of the plate-shaped member is stabilized. In addition,according to an embodiment of the present disclosure, contact betweenthe portion of the plate-shaped member supported by the support body andthe bag body can be reduced.

BRIEF DESCRIPTION OF DRAWINGS

Various embodiments of the invention are illustrated in the drawings, inwhich:

FIG. 1 is a perspective schematic view of an example configuration of avehicle seat, according to an embodiment of the present disclosure;

FIG. 2 is a front schematic view of an example state in which portionsof the vehicle seat of FIG. 1 support corresponding portions of a seatedpassenger body, according to an embodiment;

FIG. 3 is a block diagram of an example system configuration forexecuting correction control of a seating posture, according to anembodiment;

FIG. 4 is a front schematic view of an example seat back frameconfiguration of an embodiment of the present disclosure;

FIG. 5 is a front schematic view of an example state in which aplate-shaped member is detached from a seat back frame of the embodimentof the present disclosure;

FIG. 6 is a cross-sectional view of shoulder support portions of anexample seat back along the horizontal plane, according to anembodiment;

FIG. 7 is a cross-sectional view of the shoulder support portions of theexample seat back along the vertical plane, according to an embodiment;

FIG. 8 is a front schematic view of example fixing positions of each bagbody and support positions of the plate-shaped member, according to anembodiment;

FIG. 9 is a rear view of a skeleton (the right half) and skeletalmuscles (the left half) of a human;

FIG. 10 is a front schematic view of an example arrangement positions ofsensors, according to an embodiment;

FIG. 11 is a front schematic view of an example variation of a fixingstructure of the bag body, according to an embodiment;

FIG. 12 is a front schematic view of an example position relationshipamong the bag bodies and the plate-shaped member at the shoulder supportportions, according to an embodiment;

FIG. 13 is a side schematic view of an example mechanism configured tosupport the knees of the legs of the seated passenger (No. 1), accordingto an embodiment;

FIG. 14 is a side schematic view of the example mechanism configured tosupport the knees of the legs of the seated passenger (No. 2), accordingto an embodiment; and

FIG. 15 is a side schematic view of an example variation of themechanism configured to support the knees of the legs of the seatedpassenger, according to an embodiment.

DETAILED DESCRIPTION

An embodiment of a vehicle seat (referred to herein as the presentembodiment) of the present disclosure is described below with referenceto the drawings. Note that in the description below, a “front-to-backdirection” is the front-to-back direction of the vehicle seat, and iscoincident with a traveling direction when a vehicle is traveling.Moreover, a “width direction” is the width direction of the vehicleseat, and is a right-to-left direction when the vehicle seat is viewedfrom the front side thereof. Further, a “height direction” is the heightdirection of the vehicle seat, and is coincident with the verticaldirection when the vehicle is traveling on the horizontal plane.

The embodiments described below are set forth merely as examples for thesake of easy understanding of the invention, and does not limit theinvention. That is, changes and modifications can be made to theembodiments of the present disclosure without departing from the gist ofthe invention, and thus the invention includes equivalents thereof. Inparticular, the shape, material, arrangement position, etc. of variouscomponents described below can be, as desired, changed without departingfrom the gist of the invention.

In the description below, an adult male with standard proportions isassumed as a seated passenger, and when, for example, a positionrelationship with each body portion of the seated passenger is mentionedto describe the structure of each portion of the vehicle seat, the bodyof the adult male with the standard proportions is similarly used as areference. The “standard proportions” described herein are optionallyset according to, e.g., location and time of utilization of the vehicleseat of the present embodiment and regulations to be applied. In thepresent embodiment, average proportions covering 95% of adult males (inparticular, American adult males) are set as the standard proportions.

Outline Configuration of Vehicle Seat of the Present Embodiment

An outline configuration of the vehicle seat (hereinafter referred to asa “present seat S”) of the present embodiment is now described. A largeportion of a basic configuration of the present seat S is common to thatof a typical vehicle seat, except for shoulder supports A1, sidesupports A2, a lumbar support A3, and an ottoman portion A4 as describedbelow.

As illustrated in FIG. 1, the present seat S includes a seat back S1configured to support the seated passenger from the back side, a seatcushion S2 configured to support the hip of the seated passenger, and ahead rest S3 configured to support the head of the seated passenger. Theseat back S1 and the seat cushion S2 are each configured such that a padmaterial placed on a frame body is covered with a cover material. Thehead rest S3 is configured such that a pad material placed on a core ofa head portion is covered with a cover material. Moreover, the head restS3 is supported at an upper end portion of the seat back S1 through headrest pillars hp illustrated in FIG. 2.

The present seat S further includes equipment (e.g., sensors) configuredto measure a seating posture of the seated passenger, and a mechanismconfigured to adjust (e.g., correct) the seating posture. On at leastthis point, the present seat S is different from the typical vehicleseat. The configuration for seating posture adjustment in the presentseat S is described below.

Configuration for Seating Posture Adjustment

The seating posture adjustment mechanism provided at the present seat Sincludes the shoulder supports A1, the side supports A2, the lumbarsupport A3, and the ottoman portion A4. In description of thesecomponents, the shoulder supports A1 are equivalent to shoulder supportportions, and are provided respectively at positions supporting theshoulders of the seated passenger from the back side in the seat back S1as illustrated in FIG. 1. Note that in the present embodiment, theshoulder supports A1 are provided in a pair at positions separated fromeach other in the width direction.

The side supports A2 are equivalent to lateral support portions. Asillustrated in FIG. 1, the side supports A2 are provided at respectiveend portions of the seat back S1 in the width direction, and laterallysupport the trunk of the body of the seated passenger. The lumbarsupport A3 is equivalent to a waist support portion. As illustrated inFIG. 1, the lumbar support A3 is provided at a position supporting thewaist (in particular, a portion extending from the stomach to the waist)of the seated passenger from the back side in the seat back S1. Theottoman portion A4 is equivalent to a knee support portion. Asillustrated in FIG. 1, the ottoman portion A4 is attached to a front endof the seat cushion S2 to support the knees of the legs of the seatedpassenger from the knee back side.

In description of an example basic configuration of the above-describedsupport portions, each support portion has an air cell. The air cell isa bag body configured to freely expand/contract by inflow/outflow withair as an example of fluid. Each support portion pushes a correspondingportion of the body of the seated passenger by expansion of the aircell.

Specifically, an air cell 10 is built in each shoulder support A1, andexpands to push a corresponding one of the shoulders of the seatedpassenger from the back side. More specifically, expansion of the aircell 10 allows the shoulder support A1 to contact a corresponding one ofthe shoulders of the seated passenger, and therefore, provides apressing force to such a shoulder of the seated passenger as indicatedby a character F in FIG. 2. The pressing force F contains, asillustrated in FIG. 2, an inward component in the width direction and adownward component in the width direction. That is, the shouldersupports A1 push to wrap around the shoulders of the seated passenger.Such a function of the shoulder supports A1 can reduce displacement ofthe upper body of the seated passenger in the width direction and anupper-to-lower direction, and therefore, the seating posture during aseating period can be stably held.

For the purpose of more efficiently pushing the shoulders of the seatedpassenger, the shoulder supports A1 include a resin plate at the frontposition of the air cells 10. Although such a plate is described indetail below, each air cell 10 expands to contact a back surface of theplate, and therefore, each shoulder support A1 pushes a correspondingone of the shoulders of the seated passenger at a front surface of theplate.

A lateral air cell 4 is built in each side support A2, and expands tolaterally push the trunk of the body of the seated passenger inward inthe width direction. For the purpose of more efficiently pushing thetrunk of the body of the seated passenger, the side supports A2 includethe resin plate at the side position (the inner side position in thewidth direction) of each lateral air cell 4. Such a plate is made of amaterial similar to that of the plate of the shoulder supports A1, andeach lateral air cell 4 expands to contact the back surface (an outersurface in the width direction) of the plate. Thus, the side supports A2push the trunk of the body of the seated passenger at the front surface(an inner surface in the width direction) of the plate.

A waist air cell 8 is built in the lumbar support A3, and expands topush the waist of the seated passenger from the back side. For thepurpose of more efficiently pushing the waist of the seated passenger,the lumbar support A3 includes the resin plate at the front position ofthe waist air cell 8. Such a plate is made of a material similar to thatof the plate of the shoulder supports A1, and the waist air cell 8expands to contact the back surface of the plate. Thus, the lumbarsupport A3 pushes the waist of the seated passenger at the front surfaceof the plate.

The ottoman portion A4 includes an air cell (an ottoman air cell 30)disposed at the front end of the seat cushion S2, and the ottoman aircell 30 expands to push up the knees of the legs of the seatedpassenger. For the purpose of efficiently pushing up the knees of thelegs of the seated passenger, the ottoman portion A4 includes aband-shaped member at the front position of the ottoman air cell 30.Such a band-shaped member is normally in a suspending state, and whenthe ottoman air cell 30 expands to contact a back surface of theband-shaped member, the band-shaped member is lifted up accordingly.Thus, the ottoman portion A4 supports the knees of the legs of theseated passenger at a front surface (an upper surface) of the liftedband-shaped member. Note that the band-shaped member is described indetail below.

Expansion and contraction of the air cell (the air cells 10, the lateralair cells 4, the waist air cell 8, and the ottoman air cell 30) providedat each support portion are controlled by a control system CS formed inthe vehicle equipped with the present seat S. As illustrated in FIG. 3,the control system CS includes a sensor group for measuring the seatingposture of the seated passenger, a controller 50, a compressor 52, andan air supply passage 53 connected to the compressor 52. The air supplypassage 53 is branched and connected to each air cell, and anelectromagnetic valve 54 is provided at a halfway position of eachbranched air supply passage 53.

The sensor group includes a shape sensor, a body pressure sensor, aweight sensor, etc. mounted on the present seat S. This sensor groupmeasures index values for the seating posture, the index valuesincluding, for example, a skeleton curving state, pressure distributionin the vicinity of the shoulders, pressure distribution in each portionof the back, pressure distribution in the vicinity of the waist,pressure distribution in an area extending from the hip to each kneeback, and a body weight.

A shape sensor 40 and body pressure sensors 41 as illustrated in FIG. 10is referred to herein as the sensors of the sensor group provided in theseat back S1. The shape sensor 40 is formed of a shape sensing opticalfiber having flexibility, and is configured to bend along a skeletoncurving shape of the seated passenger to detect the posture of theseated passenger and output a signal corresponding to a detectionresult. Moreover, as illustrated in FIG. 10, the shape sensor 40 isdisposed at a center portion of the seat back S1 in the width directionto properly bend along the skeleton (e.g., the spine) of the seatedpassenger.

Each body pressure sensor 41 is formed in a substantially strip filmshape, and includes a detector 41 a as a sensor body and a transmissionpath 41 b for a signal output from the detector 41 a. Each body pressuresensor 41 is interposed between a pad material P1 and the cover materialwhich form the seat back S1. The body pressure sensors 41 are arrangedrespectively at body pressure distribution measurable positions in thevicinity of the shoulders, the entirety of the back, and the vicinity ofthe waist of the seated passenger. More specifically, each body pressuresensor 41 is disposed at a position apart from the shape sensor 40 inthe width direction. Specifically, as illustrated in FIG. 10, theplurality of body pressure sensors 41 are provided in a landscapeorientation at the side positions of the shape sensor 40, and arearranged in the upper-to-lower direction.

The controller 50 includes an electronic control unit (ECU) mounted onthe vehicle, and is configured to drive each support portion based onthe measurement result of each sensor of the sensor group. In anembodiment, after a proper control amount has been set from themeasurement results of various sensors, the controller 50 starts thecompressor 52 to open each electromagnetic valve 54. Thus, the volume ofair corresponding to the set control amount is injected into each aircell. As a result, each support portion is driven by a drive amountcorresponding to the above-described control amount.

Then, each support portion (specifically, the shoulder supports A1, theside supports A2, and the lumbar support A3) is driven to press acorresponding portion of the body of the seated passenger. With thisconfiguration, the posture (the seating posture) of the passenger seatedon the present seat S is corrected, and then, the seated passenger isheld in the corrected posture during the seating period.

Note that in the present embodiment, air is injected into each air cellto drive a corresponding one of the support portions, and in thismanner, such an air cell expands. However, types of fluid other than airmay be injected into a bag body other than the air cell, and in thismanner, such a bag body may expand.

Internal Configuration of Seat Back

Next, an internal structure of the seat back S1 of the present seat S isdescribed with reference to FIGS. 4 and 5. FIG. 4 is a view of a seatback frame Sf1 from the front side, and FIG. 5 is a view in the state inwhich a resin plate 20 (described below) is detached from the seat backframe Sf1 illustrated in FIG. 4.

As illustrated in FIGS. 4 and 5, the seat back frame Sf1 forming aframework of the seat back S1 is provided in the seat back S1. The seatback frame Sf1 is a substantially rectangular frame body as viewed fromthe front side, and includes an upper frame 1, a pair of lateral frames2, and a lower coupling frame 3.

The upper frame 1 is a portion coupling upper ends of the pair oflateral frames 2, and is configured such that a metal pipe is processedto bend in an inverted U-shape. Of the upper frame 1, a portionextending along the width direction forms an upper end portion of theseat back frame Sf1. A predetermined region (e.g., a region positionedslightly on the outer side with respect to the center in the widthdirection) of such a portion is attached to tubular pillar supportportions 7. Each head rest pillar hp extending from a lower portion ofthe head rest S3 is inserted into a corresponding one of the pillarsupport portions 7, and therefore, the head rest S3 is positioned abovethe upper frame 1.

The pair of lateral frames 2 are arranged separated from each other inthe width direction at the seat back frame Sf1, and extend in the heightdirection. The pair of lateral frames 2 and downwardly-extendingportions of the upper frame 1 together form respective end portions ofthe seat back frame Sf1 in the width direction. As illustrated in FIG.5, each lateral frame 2 includes a flat plate-shaped lateral plate 2 a,and a front edge portion 2 b bending inward in a U-shape from a frontend portion of the lateral plate 2 a. Of each lateral plate 2 a, aninner surface in the width direction is attached to a corresponding oneof the lateral air cells 4 forming the side supports A2.

The lower coupling frame 3 forms a lower end portion of the seat backframe Sf1, and couples lower end portions of the lateral frames 2.

In further description of the internal structure of the seat back S1, aspace is, as illustrated in FIG. 5, formed between one end portion andthe other end portion of the seat back frame Sf1 in the width direction.In the above-described space, a pressure receiving plate 5 formed as aplate-shaped member is disposed. The pressure receiving plate 5 is aresin member configured to receive pressure when the back of the seatedpassenger leans on the seat back S1, and is formed in a generallyvertically-elongated rectangular shape as viewed from the front side.Note that the shape of the pressure receiving plate 5 is not limited tothe shape illustrated in FIG. 5, and may be other shapes, in otherembodiments.

In description of the configuration of the pressure receiving plate 5with reference to FIG. 5, the pressure receiving plate 5 includes anupper portion 5 u positioned on the uppermost side, a center portion 5 vwider than the upper portion 5 u, and a lower portion 5 w extendingdownward. In the present embodiment, the upper portion 5 u, the centerportion 5 v, and the lower portion 5 w are integrally formed to form thesingle pressure receiving plate 5.

The upper portion 5 u is positioned on the inner side of the upper frame1, and is positioned at the back of the shoulders of the seatedpassenger when the passenger is seated on the present seat S. The aircells 10 forming the shoulder supports A1 are fixed to a front surfaceof the upper portion 5 u. That is, in the present seat S, the pressurereceiving plate 5 has original functions thereof, as well as having afunction as the member for fixing the air cells 10, i.e., a fixingmember. Since the pressure receiving plate 5 is utilized as the memberfor fixing the air cells 10 as described above, the number of componentsis reduced as compared to the case of separately providing the fixingmember, and the configuration of the seat back frame Sf1 can be furthersimplified.

In the present embodiment, there are two shoulder supports A1, and theair cells 10 are provided respectively for the shoulder supports A1.That is, in the present embodiment, the two air cells 10 are fixed tothe upper portion 5 u as the fixing member. More specifically, the twoair cells 10 are, as illustrated in FIG. 5, arranged symmetrically withrespect to the center of the seat back S1 in the width direction, andare each disposed in such an inclined orientation that the air cell 10is positioned lower toward the outer side in the width direction.

Note that in the present embodiment, the upper portion 5 u is in thehorizontally-elongated rectangular shape as viewed from the front side,but the present disclosure is not limited to such a shape. As indicatedby dashed lines in FIG. 5, the upper portion 5 u may be in the followingshape: upper corners of the upper portion 5 u are chamfered such that anouter edge (e.g., a portion of the outer edge positioned on the upperside) of the upper portion 5 u is along the air cell 10 in the inclinedorientation.

The center portion 5 v is disposed at a position sandwiched between thelateral frames 2. Moreover, the center portion 5 v is configured suchthat each end portion of the center portion 5 v in the width directionslightly bends forward with respect to a center portion of the centerportion 5 v in the width direction.

The lower portion 5 w is slightly narrower than the upper portion 5 u,and a lower end of the lower portion 5 w extends downward to reach thevicinity of the lower coupling frame 3. As illustrated in FIG. 5, thewaist air cell 8 forming the lumbar support A3 is disposed at a positionextending over the center portion 5 v and the lower portion 5 w on afront surface of the pressure receiving plate 5. That is, the pressurereceiving plate 5 is the fixing member for fixing the air cells 10forming the shoulder supports A1, and is also a fixing member for fixingthe waist air cell 8 forming the lumbar support A3.

The pressure receiving plate 5 configured as described above is attachedto a body of the seat back frame Sf1 through coupling wires 5 a havingelasticity. More specifically, the coupling wires 5 a are locked at theupper portion 5 u and the lower portion 5 w of the pressure receivingplate 5. The coupling wire 5 a locked at the lower portion 5 w isprovided to bridge between the pair of lateral frames 2. Of such acoupling wire 5 a, respective end portions are hooked on the lateralframes 2, and a center portion is locked at a locking portion (notshown) formed on a back surface of the lower portion 5 w.

The coupling wire 5 a locked at the upper portion 5 u is provided tobridge between the upper frame 1 and the upper portion 5 u. Of such acoupling wire 5 a, one end portion is fixed to the upper frame 1, andthe other end portion is locked at a locking portion (not shown) formedon a back surface of the upper portion 5 u. Note that there is nolimitation on arrangement of the coupling wire 5 a locked at the upperportion 5 u. For example, as illustrated in FIG. 5, such a coupling wire5 a may be disposed to hang the pressure receiving plate 5 from above,or may be disposed to extend in the oblique upward direction laterallyfrom the upper portion 5 u to hang the pressure receiving plate 5.

When receiving pressure from the back of the seated passenger leaning onthe seat back S1, the coupling wires 5 a warp such that the pressurereceiving plate 5 fixed to the seat back frame Sf1 through the couplingwires 5 a moves backward. Thus, the upper body of the seated passengermoderately sinks backward.

In continuous description of the internal structure of the seat back S1,the resin plate 20 formed as a plate-shaped member is disposed at thefront position of the air cells 10, the lateral air cells 4, and thewaist air cell 8. The resin plate 20 is provided to expand, in a planarshape, a pressing range in pressing of the body of the seated passengerby each air cell. That is, a back surface of the resin plate 20 contactsthe air cells, and each air cell expands in contact with a correspondingportion (specifically, the shoulders, the vicinity of the body trunklateral portions, and the vicinity of the waist) of the body of theseated passenger to press such a corresponding portion at the surface ofthe resin plate 20.

In more specific description of the configuration of the resin plate 20,the resin plate 20 is divided into the following portions: a portiondisposed at the front position of each air cell 10 as a portion of theshoulder support A1; a portion disposed at the front position (inparticular, on the inner side in the width direction) of each lateralair cell 4 as a portion of the side support A2; and a portion disposedat the front position of the waist air cell 8 as a portion of the lumbarsupport A3. Note that in the present embodiment, the above-describedthree portions are integrally formed to form the single resin plate 20.

In description of each portion of the resin plate 20, the portiondisposed at the front position of each air cell 10 as a portion of theshoulder support A1 is provided to expand the area of action of force onthe shoulder of the seated passenger in association with expansion ofthe air cell 10, and is specifically a deformable portion 21 capable ofdeforming in association with expansion of the air cell 10. Thedeformable portion 21 is disposed at an upper end portion of the resinplate 20, and is formed in a tail fin shape as viewed from the frontside as illustrated in FIG. 4. An inverted triangular cutout 24 isformed downwardly from an upper end of the deformable portion 21 at acenter portion of the deformable portion 21 in the width direction. Thecutout 24 is formed such that a tip end (a lower end) position thereofis at a position slightly lower than a center position of the deformableportion 21 in the height direction.

With the above-described cutout 24, the deformable portion 21 isseparated into two portions with respect to the cutout 24, specificallya one-end-side deformable piece 25 and another-end-side deformable piece26. The one-end-side deformable piece 25 and the other-end-sidedeformable piece 26 as the two separated portions are independentlydeformable. In other words, the cutout 24 is formed between thedeformable pieces 25, 26, and is equivalent to a separation portion forseparating the deformable pieces 25, 26.

The one-end-side deformable piece 25 and the other-end-side deformablepiece 26 are positioned at the back of the shoulders of the seatedpassenger when the back of the seated passenger leans on the seat backS1. More particularly, the one-end-side deformable piece 25 ispositioned at the back of one shoulder of the seated passenger, and theother-end-side deformable piece 26 is positioned at the back of theother shoulder of the seated passenger. That is, each of theone-end-side deformable piece 25 and the other-end-side deformable piece26 is positioned right in front of a corresponding one of the air cells10. Each of the one-end-side deformable piece 25 and the other-end-sidedeformable piece 26 deforms and curves to wrap around a correspondingone of the shoulders of the seated passenger as illustrated in FIGS. 6and 7 when a corresponding one of the air cells 10 expands. Thus, theshoulder supports A1 press the shoulders of the seated passenger.

A front area of each of the one-end-side deformable piece 25 and theother-end-side deformable piece 26 is larger than the area (inparticular, an area contacting the deformable portion 21) of the aircell 10. Thus, force generated by expansion of the air cell 10 isapplied to a larger area than the shoulder of the seated passenger.Since the area of action of the force generated by expansion of the aircell 10 is expanded by the resin plate 20 as described above, theshoulders of the seated passenger can be properly pressed even in thecase of using a relatively-small air cell 10.

In the present embodiment, since the one-end-side deformable piece 25and the other-end-side deformable piece 26 are independently deformableas described above, both shoulders of the seated passenger can beindependently pressed. As a result, force for pressing the shoulder ofthe seated passenger to stably hold the posture of the seated passengercan be adjusted separately for the right and left shoulders. Further, asillustrated in FIG. 4, a portion of an outer edge of each of theone-end-side deformable piece 25 and the other-end-side deformable piece26 is curved in an arc shape along the shoulder of the seated passenger,the outer edge portion being positioned at an upper corner portion.Since a portion of the resin plate 20 positioned at the back of eachshoulder of the seated passenger is in the shape along the shoulder ofthe seated passenger as described above, the shoulder supports A1 moreproperly push to wrap around the shoulders of the seated passenger.

The portion disposed at the front position of the waist air cell 8 as aportion of the lumbar support A3 is provided to expand the area ofaction of force on the waist of the seated passenger in association withexpansion of the waist air cell 8, and is an extension 22 positionedlower than the deformable portion 21 and extending downward. Theextension 22 is narrower than the deformable portion 21, and extendsdownward to pass between the right and left side supports A2 in a pairin the width direction. Thus, the lumbar support A3 is provided whilecontact with each side support A2 is reduced, and can push the waist ofthe seated passenger through the extension 22.

Note that in the present embodiment, a lower end of the extension 22reaches a position right above the lower coupling frame 3. Moreover, theextension 22 is formed in an arch shape slightly curved in the heightdirection. Thus, when the lumbar support A3 pushes forward, at theextension 22, the waist of the seated passenger, the waist of the seatedpassenger can be properly pushed at a relatively-gentle surface.

In the present embodiment, the deformable portion 21 and the extension22 are adjacent to each other, and a groove 23 linearly formed along thewidth direction is provided at a boundary position between thedeformable portion 21 and the extension 22. Of the resin plate 20, aboundary region between the deformable portion 21 and the extension 22,i.e., respective end portions of a formation region of the groove 23 inthe width direction, is provided with substantially triangular cutouts20 a formed inward in the width direction.

The portion disposed at the front position of each lateral air cell 4 asa portion of the side support A2 is provided to expand the area ofaction of lateral force on the trunk of the body of the seated passengerin association with expansion of the lateral air cell 4, and is alateral portion 27 positioned on each side of the extension 22. Thelateral portion 27 obliquely extends forward from each end of theextension 22 in the width direction, and a front end of the lateralportion 27 reaches the substantially same position as that of a frontend of the lateral frame 2. Moreover, the lateral portion 27 alsoextends in the upper-to-lower direction, and has the substantially sameheight as that of the extension 22. Further, in the present embodiment,the extension 22 and the lateral portion 27 are adjacent to each other,and a groove 28 linearly formed along the height direction is providedat a boundary position between the extension 22 and the lateral portion27.

In the present embodiment, the resin plate 20 is supported by thepressure receiving plate 5. That is, the pressure receiving plate 5functions as the fixing member for fixing the air cells, and alsofunctions as a support body for supporting the resin plate 20. Since thepressure receiving plate 5 is utilized as the support body of the resinplate 20 as described above, the number of components is reduced ascompared to the case of separately providing the support body, andtherefore, the configuration of the seat back frame Sf1 can be furthersimplified. The position of a portion of the resin plate 20 supported bythe pressure receiving plate 5 is described in detail below.

Fixing Positions of Each Air Cell and Support Positions of Resin Plate

Next, the fixing positions of each air cell and the support positions ofthe resin plate 20 are described with reference to FIG. 8. Note that thefixing positions of each air cell are indicated by black circles in FIG.8, and the support positions of the resin plate 20 are indicated byblack stars in FIG. 8.

First, the fixing positions of the air cell 10 of the air cells aredescribed, the air cell 10 forming the shoulder support A1. Indescription of the fixing positions of the air cell 10, the structure ofsuch an air cell is described. The air cell 10 is formed in asubstantially rectangular shape as viewed from the front side, andextends along the longitudinal direction thereof. Each end portion ofthe air cell 10 in the longitudinal direction thereof (in other words,each end portion of the air cell 10 in the extension direction thereof)is provided with a tongue-shaped protrusion 10 a extending outward inthe transverse direction of the air cell 10. The protrusion 10 a isequivalent to a fixing target portion, and forms a seating surface inattachment of a fixture such as a bolt.

The air cell 10 is fixed to the pressure receiving plate 5 with thefixtures attached respectively to the protrusions 10 a. Note that in thepresent embodiment, the single air cell 10 includes two protrusions 10 aas described above, and the two protrusions 10 a protrude in the samedirection.

In description of the fixing positions of the air cell 10, the air cell10 is fixed to the upper portion 5 u of the pressure receiving plate 5.In the present embodiment, the two protrusions 10 a provided at each aircell 10 are fixed respectively to fixing positions separated from eachother in the width direction. The “fixing position” described herein isthe position of a portion (e.g., a bolt hole) of the pressure receivingplate 5 into which the fixture attached to the protrusion 10 a of theair cell 10 is fitted.

In specific description with reference to FIG. 8, the air cell 10 in theinclined orientation is fixed to the pressure receiving plate 5 suchthat one (hereinafter referred to as an “outer end portion”) of both endportions of the air cell 10 in the longitudinal direction thereof on theouter side in the width direction is positioned lower than the other endportion (hereinafter referred to as an “inner end portion”) on the innerside in the width direction. Moreover, each of the two protrusions 10 aextends downward (in particular, inward in the width direction anddownward in the upper-to-lower direction). That is, in the presentembodiment, the protrusions 10 a are provided in a lower region atrespective end portions of the air cell 10 in the longitudinal directionthereof.

Moreover, in the present embodiment, the two air cells 10 are arrangedsymmetrically with respect to the center of the seat back S1 in thewidth direction, and a slight clearance is formed between the air cells10. Further, in the present embodiment, the air cells 10 are fixed onthe inner side of the outer edge of the upper portion 5 u of thepressure receiving plate 5 without protruding outward beyond such anouter edge.

As described above, in the present embodiment, the air cell 10 is fixedat both end portions of the air cell 10 in the longitudinal directionthereof, and therefore, is more stably fixed. The fixing positions ofthe air cells 10 are at the different positions in the width direction,i.e., the direction along the shoulder width of the seated passenger.Thus, the state, i.e., a fixed state, of each air cell 10 fixed alongthe shoulder width of the seated passenger is stabilized. With thestable fixed state, the air cells 10 can properly push the shoulders ofthe seated passenger.

The protrusions 10 a as the fixing target portions are provided in thelower region of both end portions of the air cell 10 in the longitudinaldirection thereof. Thus, an upper region of the air cell 10 is in anunfixed state, and therefore, easily moves forward in expansion. Withthis configuration, the upper region of the air cell 10 can expandforward, and as a result, the air cell 10 can press to wrap around acorresponding one of the shoulders of the seated passenger. Note thatsuch an advantageous effect is effectively provided by the air cells 10fixed to the front surface of the pressure receiving plate 5. That is,the air cells 10 are, in expansion thereof, controlled by the pressurereceiving plate 5 to expand forward. As a result, each air cell 10properly expands to push forward a corresponding one of the shoulders ofthe seated passenger.

For the fixing position of each protrusion 10 a of the air cell 10 asdescribed above, a relationship between such a fixing position and thebody of the seated passenger is taken into consideration. Of the fixingpositions for the protrusions 10 a provided at respective end portionsof the air cell 10 in the longitudinal direction thereof, the fixingposition for the protrusion 10 a provided at the inner end portion is,specifically, a position deviating, in both of the height direction andthe width direction, from a region corresponding to the shoulder bladesof the seated passenger. The “region corresponding to the shoulderblades” as described herein is a space region occupied by the shoulderblades as illustrated in FIG. 9, and the “position deviating from theregion corresponding to the shoulder blades” as described herein is aposition when each protrusion 10 a is disposed not to overlap with aportion or the entirety of the shoulder blades in the front-to-backdirection.

Of the fixing positions for the protrusions 10 a provided at respectiveend portions of the air cell 10 in the longitudinal direction thereof,the fixing position for the protrusion 10 a provided at the outer endportion is a position deviating, in both of the height direction and thewidth direction, from a region corresponding to the trapezius of theseated passenger. The “region corresponding to the trapezius” asdescribed herein is a space region occupied by the trapezius asillustrated in FIG. 9, and the “position deviating from the regioncorresponding to the trapezius” is a position when each protrusion 10 ais disposed not to overlap with a portion or the entirety of thetrapezius in the front-to-back direction.

Since the above-described positions are set as the fixing positions ofthe protrusions 10 a, a feeling of discomfort of the seated passengerwhen the above-described fixing positions are at positions overlappingwith the shoulder blades in the front-to-back direction or positionsoverlapping with the trapezius in the front-to-back direction can bereduced.

Further, the arrangement positions of the two air cells 10 are positionsdeviating, in the width direction, from a region corresponding to thebackbone of the seated passenger. The “positions deviating from theregion corresponding to the backbone” as described herein are positionswhen each protrusion 10 a is disposed not to overlap with a portion ofthe backbone in the front-to-back direction. With such a positionrelationship, the horizontal width (the length in the width direction)of the air cell 10 is more shortened as compared to the case where eachair cell 10 reaches the region corresponding to the backbone in thewidth direction. Thus, the size of the air cell 10 is reduced.

Next, the fixing positions of each lateral air cell 4 forming the sidesupport A2 are described. As in the above-described air cell 10, thelateral air cell 4 is also in a substantially rectangular shape asviewed from the front side, and extends along the longitudinal directionthereof. Each end portion of the lateral air cell 4 in the longitudinaldirection thereof is provided with a tongue-shaped protrusion 4 aextending outward in the transverse direction of the lateral air cell 4.That is, in the present embodiment, the single lateral air cell 4includes two protrusions 4 a as described above, and the two protrusions4 a protrude in the same direction.

The lateral air cell 4 is fixed in such a posture that the longitudinaldirection thereof is along the height direction and that each protrusion4 a extends inward in the width direction. Note that the fixingpositions of each of the two protrusions 4 a of the lateral air cell 4is on an inner surface of the lateral frame 2 (in particular, thelateral plate 2 a) in the width direction, and the protrusions 4 a arearranged in the upper-to-lower direction in the present embodiment.

Next, the fixing positions of the waist air cell 8 forming the lumbarsupport A3 are described. The waist air cell 8 is formed in a squareshape as viewed from the front side, and is, at an upper end thereof,fixed to the pressure receiving plate 5, more specifically the centerportion 5 v. Note that the fixing positions of the waist air cell 8 onthe pressure receiving plate 5 include two points separated from eachother in the width direction as illustrated in FIG. 8.

Each air cell at the above-described fixing positions is fixed to acorresponding one of the fixing members (the pressure receiving plate 5and the lateral frames 2). Note that the fixing position at each of theprotrusions 10 a, 4 a provided at the air cells 10 and the lateral aircells 4 is a position apart from the shape sensor 40 and the bodypressure sensors 41 as illustrated in FIG. 10. With such a positionrelationship, the air cells 10 and the lateral air cells 4 can properlyfixed without influencing measurement made by the shape sensor 40 andthe body pressure sensors 41.

FIG. 10 is a view of the arrangement positions of the sensors providedat the seat back S1, and in this figure, the air cells 10 and thelateral air cells 4 are each indicated by a dashed line for the purposeof showing the position relationship with the fixing positions of eachof these air cells. Note that FIG. 10 is schematically illustrated forthe sake of easy understanding of description, and in this figure, aconfiguration (e.g., the pillar support portions 7 are omitted from FIG.10) slightly different from an actual structure is illustrated.Moreover, in FIG. 10, the fixing positions of each air cell areindicated by dashed circles.

Next, the support positions of the resin plate 20 are described. Theresin plate 20 is supported by the pressure receiving plate 5 asdescribed above, and more specifically, is attached to the front surfaceof the pressure receiving plate 5 (in particular, the center portion 5v) with, e.g., screws. In the present embodiment, the portion of theresin plate 20 supported by the pressure receiving plate 5 is a boundaryportion between the deformable portion 21 and the extension 22, morespecifically a portion provided with the above-described groove 23.Since the resin plate 20 is, as described above, supported by thepressure receiving plate 5 at the boundary portion between thedeformable portion 21 and the extension 22, the resin plate 20 can beproperly supported without difficulty when the deformable portion 21 andthe extension 22 push the body of the seated passenger. Of the resinplate 20, the portion provided with the groove 23 as a bending startpoint particularly includes the support positions, and therefore, thedifficulty when the deformable portion 21 and the extension 22 push thebody of the seated passenger can be more effectively reduced.

In the present embodiment, the position of the portion of the resinplate 20 supported by the pressure receiving plate 5 is a positionreaching, in both of the height direction and the width direction, aregion corresponding to the ninth cervical spine of the seatedpassenger. The “region corresponding to the ninth cervical spine” asdescribed herein is a space region occupied by the ninth cervical spineillustrated in FIG. 9, and the “position reaching the regioncorresponding to the ninth cervical spine” is a position when disposedto overlap with a portion or the entirety of the ninth cervical spine inthe front-to-back direction. With such a position relationship, theresin plate 20 can be more stably supported.

More specifically, at the position of the ninth cervical spine, adisplacement when the seating posture of the seated passenger changes issmaller than that at other portions (i.e., a displacement at otherportions of the thoracic vertebra). Thus, as long as each supportposition of the resin plate 20 reaches the region corresponding to theninth cervical spine, a support state of the resin plate 20 can befurther stabilized.

In the present embodiment, the support positions of the resin plate 20are, as illustrated in FIG. 8, at plural points (three points in thecase illustrated in FIG. 8) in a line along the width direction. Asillustrated in this figure, each support position of the resin plate 20and the fixing positions of each air cell 10 on the pressure receivingplate 5 are positions different from each other in the width direction.With such a position relationship, contact between the portion of theresin plate 20 supported by the pressure receiving plate 5 and each aircell 10 is, in the present embodiment, reduced so that the resin plate20 can be more properly supported.

Further, each support position of the resin plate 20 is the positionapart from the shape sensor 40 and the body pressure sensors 41 asillustrated in FIG. 10. With such a position relationship, the resinplate 20 can be properly supported without influencing measurement madeby the shape sensor 40 and the body pressure sensors 41. Note that inFIG. 10, only the deformable portion 21 and the extension 22 of theresin plate 20 are indicated by dashed lines, and the lateral portions27 are omitted. Moreover, in FIG. 10, each support position of the resinplate 20 is indicated by a dashed star.

In the present embodiment, the member for fixing the air cells 10 andthe support body of the resin plate 20 are formed of the same member,specifically the single pressure receiving plate 5. However, the presentdisclosure is not limited to such a configuration. For example, asillustrated in FIG. 11, the member for fixing the air cells 10 and thesupport body of the resin plate 20 may be separately prepared asindividual bodies.

In description of the configuration of FIG. 11, the member for fixingthe air cells 10 is formed of a plate-shaped first plate member 81, andthe support body of the resin plate 20 is formed of a second platemember 82. The first plate member 81 is tall to some extent in theheight direction, and bridges between the pair of lateral frames 2 inthe width direction. The air cells 10 are fixed to a front surface ofthe first plate member 81. That is, the first plate member 81 isequivalent to the upper portion 5 u of the pressure receiving plate 5,and the air cells 10 are fixed at similar fixing positions by a similarfixing method as in the case of using the pressure receiving plate 5 asthe fixing member.

Note that the fixing position (indicated by a dashed circle in FIG. 11),which is included in the fixing positions for the protrusions 10 aprovided at respective end portions of the air cell 10 in thelongitudinal direction thereof and which is for the protrusion 10 a onthe lower side, is in a lower region of the front surface of the firstplate member 81 as illustrated in FIG. 11. With this configuration, theheight (the length in the upper-to-lower direction) of the first platemember 81 is more shortened as compared to the case where theabove-described fixing positions are in a center region of the frontsurface of the first plate member 81. As a result, an increase in thesize of the first plate member 81 can be suppressed.

The second plate member 82 is, to some extent, separated from the firstplate member 81 on the lower side thereof, and extends downward. Theresin plate 20 is attached to a front surface of the second plate member82, and therefore, is supported by the second plate member 82. That is,the second plate member 82 is equivalent to the center portion 5 v ofthe pressure receiving plate 5, and supports the resin plate 20 atsimilar support positions by a similar support method as in the case ofusing the pressure receiving plate 5 as the support body.

Note that the support positions (indicated by dashed stars in FIG. 11)of the resin plate 20 on the second plate member 82 are at an upper endportion of the second plate member 82 as illustrated in FIG. 11, and areat plural points (three points in the case illustrated in FIG. 11) in aline along the width direction, for example. In the present embodiment,the fixing positions of the air cells 10 on the first plate member 81and each support position of the resin plate 20 on the second platemember 82 are preferably positions different from each other in thewidth direction. That is, the above-described position relationshipreduces contact between a portion of the resin plate 20 supported by thesecond plate member 82 and each air cell 10, and the resin plate 20 isproperly supported.

As described above, other plate-shaped members than the pressurereceiving plate 5 may be used as the member for fixing the air cells 10,but members other than the plate-shaped member may be used. For example,the air cells 10 may be fixed to an elastic member bridging between thelateral frames 2, specifically a spring member (e.g., an S-spring).

Position Relationship Among Air Cells and Resin Plate

Next, a position relationship between each air cell 10 forming theshoulder support A1 and the deformable portion 21 of the resin plate 20is described with reference to FIG. 12. FIG. 12 is a view of theposition relationship between each air cell 10 and the deformableportion 21. Note that for the sake of easy understanding of description,only the air cells 10 and the resin plate 20 are illustrated in FIG. 12.When a position relationship between the one-end-side deformable piece25 and the air cell 10 is horizontally reversed, such a reversedposition relationship is coincident with a position relationship betweenthe other-end-side deformable piece 26 and the air cell 10. For thisreason, only the position relationship between the one-end-sidedeformable piece 25 and the air cell 10 is described below.

As illustrated in FIG. 12, the air cell 10 and the one-end-sidedeformable piece 25 are arranged such that the center positions thereofare substantially coincident with each other. The “center position” ofthe air cell 10 as described herein is a center position in both of thelongitudinal direction and the transverse direction (the directionperpendicular to the longitudinal direction) of the air cell 10.Moreover, the “center position” of the one-end-side deformable piece 25is the center position of the one-end-side deformable piece 25 in bothof the width direction and the height direction. Note that one end ofthe one-end-side deformable piece 25 in the width direction correspondsto an outermost portion of the one-end-side deformable piece 25 in thewidth direction, and the other end of the one-end-side deformable piece25 in the width direction corresponds to a portion where a tip end ofthe above-described cutout 24 is positioned.

On the other hand, each air cell 10 is fixed to the pressure receivingplate 5 at the protrusions 10 a provided in the lower region atrespective end portions of such an air cell 10 in the longitudinaldirection thereof. The “lower region” described herein is a regionpositioned on the lower side when the air cell 10 is divided by avirtual line passing through the center position of the air cell 10along the longitudinal direction thereof. Conversely, the “upper region”is a region positioned on the upper side when the air cell 10 is dividedby the above-described virtual line.

An air supply port (not shown) provided at each air cell 10 ispositioned at a point substantially coincident with the center positionof the air cell 10 as viewed from the front side. Thus, the air cell 10begins expanding preferentially from the center position of the air cell10. Thus, when the air cell 10 expands, the unfixed upper regionselectively deforms. Of the one-end-side deformable piece 25 deformingin association with expansion of the air cell 10, a portioncorresponding to the upper region, specifically a portion positioned onthe upper side with respect to the center position of the one-end-sidedeformable piece 25, deforms forward.

Further, in the present embodiment, each air cell 10 is fixed in such aninclined orientation that the outer end portion of both end portions ofthe air cell 10 in the longitudinal direction thereof is positionedlower than the inner end portion. Thus, when the one-end-side deformablepiece 25 deforms in association with expansion of the air cell 10, theone-end-side deformable piece 25 bends starting from a broken linepassing through the center position of the one-end-side deformable piece25 along the longitudinal direction of the air cell 10 in the inclinedorientation. Accordingly, the force containing the inward component inthe width direction and the downward component in the width directionacts on the shoulders of the seated passenger from the shoulder supportsA1 of the seat back S1. As a result, the shoulders of the seatedpassenger are held with the shoulder supports A1 wrapping around theshoulders, and therefore, the seating posture is stabilized.

Method for Fixing Air Cell at Ottoman Portion

Next, the method for fixing the air cell, i.e., the ottoman air cell 30,at the ottoman portion A4 is described. In description of the method forfixing the ottoman air cell 30, the band-shaped member (hereinafterreferred to as a “band-shaped support member 31”) provided at the frontposition of the ottoman air cell 30 is described. The band-shapedsupport member 31 is lifted up when the ottoman air cell 30 expands, andthe knees of the legs of the seated passenger are placed on a frontsurface (an upper surface) of the band-shaped support member 31.

In the present embodiment, the band-shaped support member 31 includes aplurality of links 31 a coupled together. Each link 31 a is formed of ametal body elongated in the width direction, and adjacent ones of thelinks 31 a are coupled together with a hinge such that one of the links31 a is rotatable relative to the other one of the links 31 a. Thecoupled links 31 a expand in a canopy shape to form the band-shapedsupport member 31. When the ottoman air cell 30 expands, the band-shapedsupport member 31 configured as described above supports the knees ofthe legs of the seated passenger at a flat support surface formed by thecontinuously-coupled links 31 a as illustrated in FIG. 13.

On the other hand, the ottoman air cell 30 is, in the front-to-backdirection, interposed between the band-shaped support member 31 and asuspending wall 71 provided at a front end portion of a cushion frameSf2 forming a framework of the seat cushion S2, as illustrated in FIG.14. Moreover, an upper end portion of the ottoman air cell 30 isprovided with a protrusion 32, and is fixed to the suspending wall 71with a fixture such as a screw attached to the protrusion 32. Note thatthe above-described protrusion 32 is a sheet-shaped portion havingflexibility, and is freely bendable.

In the present embodiment, in order to dispose anexpandable/contractible air cell body of the ottoman air cell 30 on theupper side such that the air cell body is positioned as close aspossible to the legs of the seated passenger, the protrusion 32 is fixedto an upper end surface of the suspending wall 71 with the protrusion 32being bent backward. With this configuration, the ottoman air cell 30can be disposed on the more upper side as compared to the configurationin which the protrusion 32 is fixed to a front surface of the suspendingwall 71. Moreover, the fixing method employed as described above allowsthe air cell body to expand in an upper forward direction (indicated byan arrow in FIG. 13), and as a result, the knees of the legs of theseated passenger can be properly supported.

Note that the method for fixing the ottoman air cell 30 is not limitedto the above-described contents, and for example, may be configured asillustrated in FIG. 15. In the configuration illustrated in FIG. 15, theabove-described protrusion 32 is provided at a lower end portion of theottoman air cell 30. The protrusion 32 is fixed to the front surface ofthe suspending wall 71. Since the protrusion 32 is provided at the lowerend portion of the ottoman air cell 30 as described above, an upper endof the ottoman air cell 30 can be disposed on the more upper side.Moreover, an upper portion of the ottoman air cell 30 is not fixed, andtherefore, the ottoman air cell 30 easily expands forward in expansion.With this configuration, the air cell body is closer to the knees of thelegs of the seated passenger, and as a result, the knees of the legs ofthe seated passenger can be properly supported.

TABLE OF REFERENCE NUMERALS  1: upper frame  2: lateral frame 2a:lateral plate 2b: front edge portion  3: lower coupling frame  4:lateral air cell 4a: protrusion  5: pressure receiving plate (fixingmember, support body) 5a: coupling wire 5u: upper portion 5v: centerportion 5w: lower portion  7: pillar support portion  8: waist air cell10: air cell (bag body) 10a: protrusion (fixing target portion) 20:resin plate (plate-shaped member) 20a: cutout 21: deformable portion 22:extension 23: groove 24: cutout 25: one-end-side deformable piece 26:other-end-side deformable piece 27: lateral portion 28: groove 30:ottoman air cell 31: band-shaped support member 31a: link 32: protrusion40: shape sensor 41: body pressure sensor 41a: detector 41b:transmission path 42: capacitance sensor 50: controller 52: compressor53: air supply passage 54: electromagnetic valve 71: suspending wall A1:shoulder support (shoulder support portion) A2: side support A3: lumbarsupport A4: ottoman portion CS: control system hp: head rest pillar P1:pad material S: present seat (vehicle seat) S1: seat back S2: seatcushion S3: head rest Sf1: seat back frame Sf2: cushion frame

1. A vehicle seat, comprising: a seat back configured to support aseated passenger from a back side of the seated passenger, wherein ashoulder support portion provided at the seat back and configured tosupport each shoulder of the seated passenger comprises a bag bodyconfigured to expand by injection of fluid, and wherein the bag bodycomprises fixing target portions at respective end portions of the bagbody in an extending direction thereof, and is attached to an inside ofthe seat back in such a manner that each of the fixing target portionsis fixed to a corresponding one of fixing positions separated from eachother in a width direction of the vehicle seat.
 2. The vehicle seat ofclaim 1, wherein the fixing target portions are provided in a lowerregion in the respective end portions of the bag body in the extendingdirection thereof.
 3. The vehicle seat of claim 1, wherein a fixingposition for a fixing target portion deviates from a regioncorresponding to shoulder blades of the seated passenger on the vehicleseat in both of a height direction of the vehicle seat and the widthdirection, and wherein the fixing target portion of the fixing targetportions provided at respective end portions of the bag body in theextending direction thereof is located in an inner side in the widthdirection.
 4. The vehicle seat of claim 1, wherein an arrangementposition of the bag body is a position deviating from a regioncorresponding to a backbone of the seated passenger on the vehicle seatin the width direction.
 5. The vehicle seat of claim 1, wherein a fixingposition for a fixing target portion deviates from a region on thevehicle seat corresponding to a trapezius of the seated passenger inboth of a height direction of the vehicle seat and the width direction,wherein the fixing target portion of the fixing target portions providedat respective end portions of the bag body in the extending directionthereof is located in an outer side in the width direction.
 6. Thevehicle seat of claim 1, wherein the seat back comprises a seat backframe forming a framework of the seat back, and a plate-shaped fixingmember disposed between one end portion and another end portion of theseat back frame in the width direction, and wherein the fixing positionsare on a front surface of the plate-shaped fixing member.
 7. The vehicleseat of claim 6, wherein, a fixing position for a fixing target portionis located in a lower region of the front surface, the fixing targetportion of the fixing target portions provided at respective endportions of the bag body in the extending direction thereof is locatedin a lower side.
 8. The vehicle seat of claim 1, wherein the seat backcomprises a plate-shaped member disposed at a front position of the bagbody, wherein the plate-shaped member comprises a deformable portionhaving a back surface that contacts the bag body and is configured todeform by expansion of the bag body contacting the back surface, and anextension positioned lower than the deformable portion and extendingdownward, wherein the plate-shaped member is supported by a support bodyprovided in the seat back, and wherein a portion of the plate-shapedmember is provided between the deformable portion and the extension,wherein the portion of the plate-shaped member is supported by thesupport body.
 9. The vehicle seat of claim 8, wherein a position of theportion of the plate-shaped member reaches a region corresponding to aninth cervical spine of the seated passenger on the vehicle seat in bothof a height direction of the vehicle seat and the width direction,wherein the portion of the plate-shaped member is supported by thesupport body.
 10. The vehicle seat of claim 8, wherein the seat backcomprises a seat back frame forming the framework of the seat back, anda plate-shaped fixing member disposed between one end portion andanother end portion of the seat back frame in the width direction,wherein the fixing positions are on the front surface of theplate-shaped fixing member, and wherein a position of the portion of theplate-shaped member and the fixing positions on the front surface aredifferent from each other in the width direction, wherein the portion ofthe plate-shaped member is supported by the support body.